The present invention generally relates to parts mounting apparatuses used for mounting electronic parts on a circuit board through suction on the electronic parts, etc. and more particularly, to a parts mounting apparatus having a suction nozzle made of transparent material.
Conventionally, as shown in FIG. 1, in order to mount electronic parts on a circuit board, an electronic part P to be mounted is sucked by a suction nozzle 51 at a parts feeding position 52 and then, the suction nozzle 51 is displaced to a recognition the position where position of the electronic part P sucked by the suction nozzle 51 is detected by a recognition camera 53. Subsequently, the suction nozzle 51 is displaced to a position confronting a mounting position of the electronic part P on a circuit board B. After inaccurate positioning of the electronic part P has been corrected, the electronic part P is mounted at a predetermined position on the circuit board B.
However, in the known parts mounting apparatus referred to above, the suction nozzle 51 is accurately positioned at the recognition the position in the course of displacement of the suction nozzle 51 towards the circuit board B after the electronic part P has been sucked by the suction nozzle 51. Then, after position of the electronic part P relative to the suction nozzle 51 has been recognized, the suction nozzle 51 is again displaced. Therefore, the known parts mounting apparatus has a drawback that the cycle time for mounting one electronic part P becomes long, thereby resulting in reduction of mounting efficiency.
Thus, the assignee of the present inventors proposed earlier an electronic parts mounting apparatus which includes a suction nozzle made of light transmitting material and a recognition means for recognizing the position, shape, etc. of an electronic part sucked by the suction nozzle. In this prior art electronic parts mounting apparatus, space arround the suction nozzle is required to be formed into a light transmitting suction chamber such that not only the electronic part vacuum-sucked by the suction nozzle but also the electronic part as a whole can be recognized. To this end, space arround the suction nozzle is closed by a light transmitting plate spaced a proper distance from the suction nozzle such that the suction chamber is defined. However, since the suction nozzle is detachably mounted on a mounting head in order to make it possible to wash the suction nozzle, air leakage at the mounting portion between the suction nozzle and the mounting head is large, so that it is difficult to increase the degree of vacuum of the suction chamber and thus, it is difficult to pick up a heavy electronic part.
Furthermore, in this prior art electronic parts mounting apparatus, since suction and cancellation of suction are required to be repeated at high speed, the volume of the suction chamber should be made small. Hence, the distance between the suction nozzle and the light transmitting plate becomes short and thus, dust, etc. mixed into the suction air adhere to the suction nozzle as well as the light transmitting plate. Accordingly, both the suction nozzle and the light transmitting plate are detachably mounted so they can be washed easily. As a result, since it becomes more difficult to increase the degree of vacuum of the suction chamber and the mounting construction of the suction nozzle becomes complicated, the prior art electronic parts mounting apparatus has disadvantages such that positioning accuracy of the suction nozzle is reduced and washing of the suction nozzle and the light transmitting plate becomes troublesome.